Two magnetic poles of pole strength 20 Am and 15 Am are kept at a distance of 10cm. The force acting on one of the poles is ...... ..

Options

A. `3 xx 10^(2)` N
B. `3 xx 10^(-3)` N
C. `2 xx 10^(-3)` N
D. `3 xx 10^(-5)` N

Answer

B

Explanation

Here `P_(1) = 20 "Am", P_(2) = 15 "Am"`,
`r= 10 cm = 10 xx 10^(-2) `m
`F = (mu_0)/( 4pi ) . (P_1 P_2)/( r^2) `
`= (4pi xx 10^(-7) )/( 100 xx 10^(-4)) therefore F=3 xx 10^(-3) N`